Spirally wound paper tube

ABSTRACT

A SPIRALLY WOUND PAPER TUBE INCLUDING A RELATIVELY NARROW STRIP OF PAPER SPIRALLY WOUND IN UNDERLYING RELATIONSHIP WITH A RELATIVELY WIDE PAPER STRIP WITH ADHERSIVE THEREBETWEEN AND WITH THE SPIRAL SEAM OF THE RELATIVELY WIDE PAPER STRIP POSITIONED APPROXIMATELY INTERMRDIATE THE SIDE EDGES OF THE NARROW STRIP.

NOV. 2,, 1971 c, K DUNLAP, JR EIAL 3,616,819

SPIRALLY WOUND PAPER TUBE Original Filed Jan. 5, 1966 INVENTOR CHARLES K. DUNLAP, JR. AND JAMES A. FINK United States Patent 01 ice Patented Nov. 2, 1971 US. Cl. 138-144 2 Claims ABSTRACT OF THE DISCLOSURE A spirally wound paper tube including a relatively narrow strip of paper spirally wound in underlying relationship with a relatively wide paper strip with adhesive therebetween and with the spiral seam of the relatively wide paper strip positioned approximately intermediate the side edges of the narrow strip.

This application is a division of the pending application entitled Method of Producing a Spirally Wound Tube, Ser. No. 519,819, filed by the applicants herein on Jan. 5,1966, now US. Pat. No. 3,468,733.

Spiral tubes and in particular spirally Wound paper tubes are in widespread use today for a multitude of purposes such as the winding of sheet material including paper, plastic film and the like. Such spiral tubes are required to possess certain minimum strength characteristics such as beam and crush strength so as to receive the windings of sheet material without collapsing. In order to provide the desired degree of strength in such spirally wound paper tubes, they are commonly formed from a plurality of plies of spirally wound paper strips arranged in staggered relationship with adhesive therebetween to hold the plies together in the spiral tube form.

As can be understood, such a spiral tube generally requires at least two plies for mutual retaining engagement so as to hold the plies together in the spiral tube form. This required use of at least two plies adds materially to the cost of such a tube from both the standpoint of the paper required for the additional plies as well as the additional adhesive required to secure the overlying plies together. Such additional cost factors represent the difference between commercial success and failure in many instances where it is required that an absolute minimum of cost be represented by the spiral tube or core on which the relatively costly sheet material is wrapped.

Accordingly, a primary object of this invention is to provide a new and novel spiral tube.

A further object of this invention is to provide a new and novel spiral tube utilizing only a single body ply.

Still another object of this invention is to provide a new and novel spiral tube of one body ply construction which requires only a minimum amount of paper and adhesive so as to be relatively inexpensive to manufacture but at the same time is sufficiently strong and durable so as to be capable of being wound with a wide variety of sheet materials.

Other objects and advantages of the invention will become apparent from the following description taken in connection with the accompanying drawing.

The objects stated above and other related objects in this invention are accomplished by winding a relatively wide body ply of strip material such as paper into a tubular body having a spiral seam utilizing a spiral tube winding operation. At the same time, a relatively narrow strip of material, preferably also paper, having adhesive applied thereto is spirally wound over the spiral seam on the tubular body. This relatively narrow paper strip is thus adhesively secured to the edge portions of the body ply adjacent the spiral seam and maintains the body ply spirally wound into the tubular body to form a spirally wound paper tube.

The novel features which are believed to be characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation may be best understood by reference to the following description taken in conjunction with the accompanying drawing in which:

FIG. 1 is a side view of the spiral tube of the invention;

FIG. 2 is a schematic plan view of winding aparatus for forming the spiral tube of FIG. 1 and for carrying out the method of the invention;

FIG. 3 is an enlarged plan view of a portion of the mandrel of the winding apparatus of FIG. 2;

FIG. 4 is a sectional view taken substantially along line 44 of FIG. 1 in the direction of the arrows;

FIG. 5 is a view similar to FIG. 2 showing a modification of the invention; and

FIG. 6 is a side view of a portion of the spiral tube formed with the arrangement of FIG. 5.

Referring now to the drawing and to FIG. 1 in particular, there is shown a spiral tube formed in accordance with the invention and designated generally by the reference character T. Although the spiral tube T may be formed of any suitable material, it is preferably formed of a fibrous material such as paper.

The spiral tube T includes a relatively wide body ply 12 which is spirally wound as shown in FIG. 1 into a tubular body having an inner surface 13 and an outer surface 14. The single body ply 12 is spirally wound with the edges of adjacent convolutions in abutting relationship to form a spiral seam 16.

A relatively narrow strip 17 of material such as paper is also spirally wound over the spiral seam 16 of the tubular body formed by the body ply 12. By means of an adhesive which is preferably applied to one surface of the relatively narrow strip 17, the strip 17 is secured to edge portions of the body ply 12 adjacent the spiral tube seams 16 with the steam 16 preferably substantially intermediate the side edges of the strip 17 as shown.

In the embodiment of FIG. 1, the strip 17 is secured to the inner surface 13 of the spirally wound ply .12 and maintains the body ply 12 spirally wound into the tubular body to form the spiral tube T of the invention. Thus, the spiral tube T employs only a single body ply 12 together with a relatively narrow strip 17 which prevents the single body ply 12 from unwinding from the spirally wound tubular body forming the spiral tube T.

The spiral tube T of FIG. 1 is formed utilizing a novel method as illustrated schematically by the spiral tube winding apparatus of FIG. 2. The spiral tube winding apparatus of FIG. 2 includes a mandrel 18 supported at one end in a suitable frame 19 and a flexible endless belt 21 extending around a pair of pulleys 22, 23 at least one of which is driven for rotating and advancing the tube T in the direction of the arrow I as it is formed in the wellknown manner.

'The mandrel 18 includes a guide portion 18a adjacent the fixed end of the mandrel and a smooth cylindrical portion 18b forwardly of the section 18a having an outer diameter corresponding generally to the inner diameter of the spiral tube T defined by the strip 17. The mandrel guide portion 18a is formed with a spiral groove 23 extending substantially throughout its length which accommodates the relatively narrow paper strip 17 during the Winding operation. Thus in one embodiment of the invention, the spiral mandrel groove 23 is approximately 1 inch in Width to accommodate a strip 17 having a width of 1 inch and is approximately 0.009 inch in depth to accommodate a strip 17 of approximately 0.015 inch in thickness. The groove 13 is preferably of such a depth so as to permit the strip 17 seated therein to project above the outer surface of the mandrel portion 18a thus insuring contact with the overlying body ply 12.

In the winding of the spiral tube T by the novel method of the invention, the paper strip forming the relatively wide body ply 12 is unwound in the direction of the arrow P from a supply roll (not shown) and wound onto the mandrel 18 with the edges of adjacent convolutions in abutting relationship to form the spiral seam 16. At the same time, the relatively narrow strip 17 is similarly unwound in the direction of the arrow Q from a supply roll (not shown). The strip 17 is conducted through a glue applicator designated generally by the numeral 24 and spirally wound onto the mandrel 18 between the mandrel and the strip 12 within the mandrel groove 23.

In order to adhere the strip 17 to the body ply 12, the strip 17, advancing through the glue applicator 24 is maintained in contact with an applicator roll 26 suitably supported for rotation in the glue applicator 24. Contact between the applicator roll 26 and the strip 17 is maintained by suitable guide rolls 27 supported for rotation on the glue applicator as shown in FIG. 2 so that the applicator roll 26 applies adhesive to the surface of the strip 17 which subsequently contacts the ply 12 when the strips 12, 17 are wound onto the mandrel 18.

During the winding operation of FIG. 2, the strip 12 is positioned so as to locate the spiral seam 16 approximately intermediate the side edges of the relatively narrow strip 17 so that the strip is adhesively secured to the edge portions of the body ply 12 adjacent the spiral seam 116 as shown best in FIG. 1 to maintain the body ply 12 spirally wound into the tubular body to form the spirally wound tube T.

As the tube T formed by the strips 12., 17 wound together moves in the direction of the arrow [I by means of the belt 21, the strip 17 moves along the groove 23 throughout the mandrel portion 18a until it emerges at the groove opening 23w securely and permanently glued to the overlying body ply 12. Subsequently, further movement of the formed spiral tube T takes place along the smooth mandrel portion 1812 with the continuously formed spiral tube T cut into appropriate lengths in the wellknown manner by suitable cutoff means (not shown).

It should be understood that the paper strip 12 may be of any suitable width Within a wide range for forming the spiral tube T such as is commonly found in spiral tubes manufactured today. The width of the strip 17 need only be such as to provide for positive adhesion between the strip 17 and the edge portions of the ply 12 adjacent the seam 116 for maintaining the tube T in the Wound condition. In one embodiment of the invention, the width of the strip 17 is /3 the width of the strip 12 so that a 1 inch strip 17 is used together with a 3 inch width strip 12 to form the tube T.

FIGS. 5, 6 show a modification of the invention in which a modified method of winding is employed to produce a modified spiral tube T. The spiral tube T of the modification utilizes a relatively wide body ply 31. having an inner surface 32 and an outer surface 33. The body ply 31 is wound similarly to the body ply 12 of the embodiment of FIG. 1 with the edges of adjacent convolutions in abutting relationship to provide a-spiral seam 34.- However, the relatively narrow strip of the embodiment of FIGS. 5, 6 identified by the numeral 36 is spirally wound onto the outer surface 33 of the body ply 21 and is adhesively secured to edge portions of the body ply outer surface 33 adjacent the spiral seam 34. The strip 36 functions similarly to the strip 17 of the embodiment of FIG. 1 in that only a single body ply 31 is employed which is held spirally wound in the form of a tubular body by the strip 36 to form the spiral tube T.

In carrying out the modified method of the invention with the apparatus of BIG. 5 by means of which the tube T is produced, a smooth surfaced mandrel 41 is provided supported at one end in a frame 42 and has associated therewith a winding belt 43 extending around belt pulleys 44, 46. The strip 31 forming the relatively wide body ply of the tube T is advanced in the direction of the arrow M and spirall'y wound onto the mandrel 41 as shown. The strip 36 to which adhesive is applied in the glue applicator 47 is advanced in the direction of the arrow N and spirally wound on the outer surface of the wound strip 31 as shown over the spiral seam 34. The glue applicator 47 includes guide rolls 48 and an applicator roll 49 which applies glue to that surface of the strip 36 which contacts the underlying wound strip 31 and the strip 36 is positioned so that it is adhesively secured to the edge portions of the wound strip 31 adjacent the spiral seam 34 intermediate the side edges of the strip 36. As in the embodiment of FIGS. 1-4, the wound tube T is moved in the direction of the arrow R by means of the belt 43.

It can be seen that there has been provided with the novel construction of this invention a spirally wound tube which may be formed from relatively soft weak material such as paper and utilizing only a single body ply while achieving strength characteristics adequate to support windings of sheet material without collapsing. An outstanding feature of the invention is the elimination of a second body ply presently required to maintain spirally wound paper tubes in the wound condition utilizing present day spiral tube winding practices. 'Not only does the elimination of the second ply simplify the manufracture of the spiral tube of the invention but in addition a substantial saving in paper and adhesive costs result permititng the production of a far cheaper tube than presently manufactured for the same purposes. By the novel method for forming the spiral tube of the invention, the tube may be inexpensively and easily wound at a high production rate with an elimination of such problems as unstuck plies, and a reduction of start-up time for tube manufacture. In addition, the spiral tube of the invention may be formed selectively with the relatively narrow holding strip on the inside or outside of the single body ply without any sacrifice in utility or increase in cost thereby producing a remarkably simple commercially attractive throw-away paper tube of the type long required by purchasers.

While there has been described what at present is considered to be the preferred embodiment of the invention, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the invention.

Having thus described the invention, what is claimed 1s:

1. A spirally wound paper tube consisting of a relatively wide body ply of fibrous material spirally wound with the side adges of adjacent convolutions in abutting engagement to form a tubular body having a spiral seam; a relatively narrow, spirally wound strip of fibrous material extending over said spiral seam and adhesively secured on the outer surface of the edge portions of said relatively wide body ply adjacent said spiral seam to maintain said body ply spirally wound into said tubular body and thereby form a strong and durable spiral tube with a minimal *amount of materials to permit winding a wide 2,943,540 variety of sheet materials thereon. 3,150,575

2. A spiral tube in accordance with claim 1 wherein 3,159,515 said relatively narrow strip has a width of about /3 the 3,196,762 width of said relatively wide body ply. 5 3,457,130

References Cited UNITED STATES PATENTS 6 McBain 156-195 X Couzens et a1. 93-80 Dunlap et al 156-190 Schmeltz l56190 X Morrison 156195 X HAROLD ANSHER, Primary Examiner us. c1. X.-R.

2,046,138 6/1936 Tucker 156-490 x 2,555,380 6/1951 Stuart et al 156-19=0X 10 137, 1 1 304; 1 1- 2,751,936 6 /1956 Dunlap et a1 156195X 145 

